Many automotive fuel supply systems include a fuel tank for storing fuel. In one arrangement, a fuel delivery module including, among other things, a housing, a fuel pump, and a fuel filter may be provided for an automotive vehicle. In one arrangement, the fuel pump may be arranged in-line with one or more fuel delivery lines. In operation, fuel typically travels through the fuel filter, into the fuel pump, and to an internal combustion engine.
A traditional fuel injection pump may include a membrane or movable wall which divides the storage chamber from the drive mechanism chamber. The membrane/diaphragm can reduce the sudden loading of the storage chamber by the fuel, which has been previously brought to injection pressure and is sent into the storage chamber at the end of the feed stroke that effects the injection, by virtue of the fact that the diaphragm yields to the pressure surge against the drive mechanism chamber, which is under a lower pressure, and offsets the outflow quantity. At the same time, during the intake stroke of the pump piston, the filling process of the pump work chamber is positively supported by the simultaneous volume change in the intake chamber and drive mechanism chamber. The pressure difference in the storage chamber and the drive mechanism chamber, which acts on this pump piston during its intake stroke, powers the pump piston in the intake stroke direction and obviates the need for a separate spring for returning the pump piston from its top dead center position to its bottom dead center position after the pressure or filling stroke.
Accordingly, with reference to FIG. 1, many fuel pumps 108 implement a dampener 118 in order to dampen pressure oscillations—due to reciprocating movement of the plunger 122 in the pump 108. As is known, the plunger 122 in a fuel pump 108 engages in three processes resulting in the reciprocating movement: (1) the plunger 122 moves to take in fuel from the fuel intake joint to the pressure chamber 126; (2) the plunger 122 moves to deliver fuel from the pressure chamber 126 to the common rail; and (3) the plunger 122 moves to return fuel from the pressure chamber 126 to the fuel intake passage. The dampener 118 may be at least partially defined by at least one diaphragm 120 that is acted upon by lubrication pressure. Therefore, should a load 130 be applied to the dampener 118, it is possible to risk the structural integrity of this liquid chamber. It is understood that the region of the pump 108 containing the plunger 122 is generally more robust relative to the dampener region 134 given that the plunger 122 is generally slidable within a cylindrical structure 132 in the fuel pump 108, and therefore, the plunger region 136 is less susceptible to rupture risk in the event that a load 130 is applied to the plunger region 136.
Because of the great pressure difference between the pressure in the pressure chamber 126 and the pressure in the drive mechanism chamber, the diaphragms 120 are optimally designed for pressure fluctuations. As shown in FIG. 1, these components, including the fuel pump plunger 122, are traditionally protected by pump body 110 shown as element 110 in FIG. 1. However, when a load 130 is applied directly to pump body 110, the pump body 110 may transfer the load 130 directly to the pressure chamber 126 having at least one diaphragm 120, filled with liquid given that the pump body 110 closely encases the pressure chamber 126 (shown in FIG. 1).
Accordingly, it would be desirable in the industry to produce a fuel pump cover which is designed to deflect loads imposed on the region of a fuel pump having a pressure chamber.